CHAP1 - Product Design Theory and Methodology
CHAP1 - Product Design Theory and Methodology
CHAP1 - Product Design Theory and Methodology
LECTURE OUTLINE
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Structured methodology
• Makes decision‐making is more explicit
• Provides checklists
• Is readily documented in a structured way
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WHAT IS DESIGN?
Design Analysis
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DESIGN – DEFINITION
shape
What the product configuration
look like, what Form
size
material, how it
is made
materials
manufacturing
processes
Form Ever Follows Function
Luis Sullivan
The form of an object usually depends upon the function it will perform.
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EXAMPLE
Screwdriver
Its tip has a shape that drives the screw into the hole.
The handle is configured to conform to human hand, permitting
the application of torque and thrust.
The injection moulding process used to make the handle permits
cost effective manufacture.
The steel shank material safely transmits the torque and thrust
from the handle to the tip.
Complexity
Requires decisions on many variables and parameters.
Choice
Requires making choices between many possible
solutions at all levels, from basic concepts to the smallest
detail of shape.
Compromise
Requires balancing multiple and sometimes conflicting
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One‐way communication
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Inefficient, costly, may result in poor‐quality products
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EXAMPLE
Engineering analysis
Given the mass m of an object that has an applied force f acting on it,
determine the acceleration a.
Given the cross-section geometry of an aluminum airplane wing, we determine
the lift it produce by conducting wind tunnel experiment.
Given a cast steel engine block drawing, estimate its weight.
The solution is how the object behave (predicted behaviour)
Given that the customer desires to store 1500l of petrol, determine suitable a
storage tank. ( what is the shape and material and how its made)
Given that the customer desires to toast slices of bread, develop a product that
will perform this desired function. ( how many slices, how dark, what type of
bread)
The given information relate to the desire function and the solution is to find the
form.
fabricate
Manufacture assemble
distribute
set up
Use operate
maintain
repair
take down
Retire
disassemble
recycle
dispose
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Design effectiveness
Product cost High performance along
Product quality these dimensions should
lead to economic
Time to market
success
QUALITY
VALUE
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Adapted from M. Asimow, Introduction to Design, Prentice-Hall, Englewood Cliffs, NJ, 1962.
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Adapted from P. H. Hill, The Science of Engineering Design, Holt, Rinehart and Winston, New York
1970.
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A PROBLEM-SOLVING METHODOLOGY
Definition of the problem
Gathering of information
Generation of alternative solutions
Evaluation of alternatives and decision making
Communication of the results
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Phase I:
Conceptual Design
Phase II:
Embodiment Design
Phase III:
Detail Design
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TYPES OF DESIGNS
Original Design: Innovative design - new concept, part never
existed before
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Formulation
Original
design Selection
Part design
design Variant
Concept Design
design
Configuration Configuration
Design Design
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2) Life-Cycle Issues
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Reproduced from “Materials and Man’s Needs,” National Academy of Sciences, Washington, D.C., 1974.
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The advent of plentiful computing has produced a major change in the way engineering
design is practiced.
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Performance Codes are stated in terms of the specific requirement that is expected to be
achieved.
Prescriptive(specification) Codes state the requirements in terms of specific details and leave
no discretion to the designer.
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DESIGN REVIEW
The PDS is a detailed document that describes what the design must be in terms of:
Performance requirements
Environment in which it must operate
Product life
Quality
Reliability
Cost
Host of other design requirements
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REDESIGN
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CHARACTERISTICS OF AN ENVIRONMENTALLY
RESPONSIBLE DESIGN
Easy to disassemble
Able to be recycled
Contains recycled materials
Uses identifiable and recyclable plastics
Reduces use of energy and natural materials in its manufacture
Manufactured without producing hazardous waste
Avoids use of hazardous materials
Reduces product chemical emissions
Reduces product energy consumption
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ACKNOWLEDGEMENT
Materials used in this presentation are from :
1. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies
2. K.T. Ulrich and S. D. Eppinger, Product Design and Development. ©2003. The
McGraw-Hill Companies.
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